TW201703386A - Charging circuit and mobile terminal - Google Patents

Abstract

The present disclosure proposes a charging circuit and a mobile terminal. The charging circuit includes a first circuit connected to a charging interface, a second circuit connected to a battery, and a capacitance coupling element connected between the first circuit and the second circuit. The first circuit is used for receiving direct current for charging provided from the charging interface, and for converting the direct current into alternative current. The second circuit is used for receiving and converting the alternative current from the first circuit into direct current for charging the battery. According to the present disclosure, the DC route of the charging circuit is cut by the capacitance coupling element, i.e. the DC route of the charging circuit being free from the DC route. Accordingly, DC current from the charging interface cannot apply to the second circuit and the battery when the first circuit disables, thereby facilitating reliability of the charging circuit.

Description

Charging circuit and mobile terminal

Embodiments of the present invention relate to the field of mobile terminals, and, more particularly, to a charging circuit and a mobile terminal.

The use of mobile terminals is becoming more and more popular, and the charging problem of mobile terminals has become a major concern of mobile terminal providers.

Fig. 1 is a circuit diagram showing a charging circuit used in a conventional mobile terminal. This circuit diagram is called BUCK circuit and mainly includes: MOS transistor, control circuit, diode, inductor and battery. During charging, the control circuit controls the turn-on and turn-off of the MOS transistor to generate a varying square wave current that flows from the MOS transistor to the inductor and is regulated by the inductor to flow to the battery.

The main problem with conventional technology, or the risk, is that the MOS transistor may be broken down, causing current to pass directly through the inductor, current and voltage to check the circuit and the battery, which will cause the battery to exceed the limit voltage, resulting in catastrophic consequences.

The cause of damage to the MOS transistor can be: 1. The MOS transistor is mis-conductive, and the voltage applied across the MOS transistor exceeds the maximum withstand voltage, electrostatic breakdown or surge of the MOS transistor; 2. MOS transistor quality Bad, or manufacturing process problems; 3. Other defects, etc.

Because MOS transistors have many problems, and in order to avoid the above problems, and improve the reliability of MOS transistors, the conventional solution is to increase the resistance of the MOS transistor's on-resistance (RDSON) to improve the MOS transistor. The pressure resistance, but the high on-resistance causes the charging circuit to be easily heated, and the energy transmission efficiency is low.

Embodiments of the present invention provide a charging circuit and a mobile terminal to improve reliability of a charging circuit in a mobile terminal.

In a first aspect, a charging circuit is provided, the charging circuit is located between a charging interface of a mobile terminal and a battery, and includes: a first circuit connected to the charging interface, wherein the first circuit receives through the charging interface a direct current for charging, and converting the direct current supplied by the charging interface into alternating current; a second circuit connected to the battery, wherein the second circuit receives the alternating current output by the first circuit, and the The alternating current outputted by the first circuit is converted into direct current to charge the battery; a capacitive coupling element is located between the first circuit and the second circuit to disconnect the first circuit and the second circuit a DC path, wherein the capacitive coupling element is configured to couple an alternating current outputted by the first circuit to the second circuit when the first circuit is in normal operation, wherein the first circuit is faulty When the alternating current cannot be generated, the direct current output from the first circuit is blocked.

With reference to the first aspect, in an implementation manner of the first aspect, the first circuit is specifically configured to: charge and discharge a capacitor in the capacitive coupling component by controlling a transistor inside the first circuit, The direct current provided by the charging interface is converted into alternating current.

In conjunction with the first aspect, or any one of the foregoing implementations, in another implementation of the first aspect, the first circuit includes a bridge arm circuit and a control circuit for controlling the bridge arm circuit, wherein The control circuit controls the bridge arm circuit to alternately charge and discharge the capacitor.

With reference to the first aspect, or any one of the foregoing implementation manners, in another implementation manner of the first aspect, the capacitor in the capacitive coupling component is one of the following capacitors: a capacitor formed by a printed circuit board (PCB), and A capacitor formed by a flexible printed circuit (FPC) board.

In combination with the first aspect or any of the above implementations, in another implementation of the first aspect, the size, shape or thickness of the capacitance in the capacitive coupling element is designed based on the structure of the charging circuit.

In conjunction with the first aspect, or any one of the foregoing implementations, in another implementation of the first aspect, the first circuit comprises a bridge arm circuit, the bridge arm circuit comprising a plurality of metal oxide semiconductor field effect transistors (MOSFET).

In conjunction with the first aspect, or any one of the foregoing implementations, in another implementation of the first aspect, the second circuit comprises a rectifier circuit and a filter circuit.

In a second aspect, a mobile terminal is provided, comprising a charging interface and a battery, wherein a charging circuit as described in the first aspect or any of the above embodiments is provided between the charging interface and the battery.

In conjunction with the second aspect, in an implementation manner of the second aspect, the charging interface is a universal serial bus USB interface.

In conjunction with the second aspect, or any one of the foregoing implementation manners, in another implementation manner of the second aspect, the mobile terminal supports a normal charging mode and a fast charging mode, wherein a charging current of the fast charging mode is greater than Charging current in normal charging mode.

In the embodiment of the present invention, the DC path of the charging line is separated by the capacitive coupling element, that is, there is no DC path on the charging circuit, then, when the first circuit fails, the DC output of the charging interface is not directly output. To the second circuit and the battery, the reliability of the charging circuit is improved.

10‧‧‧Charging interface

20, 52‧‧‧ battery

30, 53‧‧‧Charging circuit

31‧‧‧First circuit

32‧‧‧second circuit

33‧‧‧Capacitive coupling elements

311, 313‧‧‧ control circuit

312‧‧‧ Half-bridge circuit

314‧‧‧Full bridge circuit

50‧‧‧Mobile terminal

51‧‧‧Charging interface

T1~T4‧‧‧O crystal

C1, C2‧‧‧ capacitor

In order to more clearly illustrate the technical solution in the embodiment of the present invention, the following will be true BRIEF DESCRIPTION OF THE DRAWINGS The drawings used in the description of the embodiments are briefly described. It is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art are not required to make progressive labor. Further drawings can also be obtained from these figures.

Fig. 1 is a circuit diagram of a charging circuit in the prior art.

Fig. 2 is a schematic block diagram of a charging circuit of an embodiment of the present invention.

Fig. 3 is a view showing an example of a charging circuit of an embodiment of the present invention.

Fig. 4 is a view showing an example of a charging circuit of an embodiment of the present invention.

Fig. 5 is a schematic block diagram of a mobile terminal according to an embodiment of the present invention.

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are a part of the embodiments of the present invention, but not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without departing from the scope of the invention shall fall within the scope of the invention.

Fig. 2 is a schematic block diagram of a charging circuit of an embodiment of the present invention. The charging circuit 30 of FIG. 2 is disposed between the charging interface 10 of the mobile terminal and the battery 20, and the charging circuit 30 includes a first circuit 31 connected to the charging interface 10, wherein the first circuit 31 passes The charging interface 10 receives DC power for charging and converts DC power provided by the charging interface 10 into AC power; a second circuit 32 is connected to the battery 20, wherein the second circuit 32 receives the first An alternating current outputted by a circuit 31, and converting alternating current outputted by the first circuit 31 into direct current to charge the battery 20; a capacitive coupling element 33 located between the first circuit 31 and the second circuit 32 , to disconnect the DC path between the first circuit 31 and the second circuit 32, wherein The capacitive coupling element 33 is configured to couple the alternating current output by the first circuit 31 to the second circuit 32 when the first circuit 31 is in normal operation, and the first circuit 31 cannot be generated due to a fault. When AC power is applied, the direct current output from the first circuit 31 is blocked.

In the embodiment of the present invention, the DC path of the charging line is separated by the capacitive coupling element, that is, there is no DC path on the charging circuit, then, when the first circuit fails, the DC output of the charging interface is not directly output. To the second circuit and the battery, the reliability of the charging circuit is improved.

It should be understood that the charging interface 10 can be a Universal Serial Bus (USB) interface, which can be a normal USB interface or a micro USB interface. In addition, it should also be understood that the battery 20 described above may be a lithium battery.

It should be understood that the second circuit 32 described above may function to adjust the current output by the first circuit 31 to a charging current suitable for charging the battery 20. The second circuit 32 may include a rectifying circuit, a filtering circuit, or a voltage stabilizing circuit. The rectifying circuit may be a diode rectifying circuit or a triode rectifying circuit, and specifically refers to a rectifying method of the prior art, which is not described in detail herein.

It should be understood that the second circuit 32 can be used to adjust the alternating current of the first circuit 31 coupled to the second circuit 32 through the capacitive coupling element 33 to a direct current suitable for charging the battery 20.

It should be noted that the first circuit 31 converts the DC power provided by the charging interface 10 into an alternating current, and the first circuit 31 can charge and discharge the capacitor in the capacitive coupling element 33, that is, the first circuit 31 passes certain control logic. The capacitor in the capacitive coupling element 33 is charged and discharged. When the control frequency of the control logic reaches a certain level, from the perspective of the capacitor, the output from the first circuit 31 is alternating current, and the capacitor has an alternating current and a blocking direct current. The function of the alternating current is transmitted to the second circuit 32 through the capacitor.

Optionally, as an embodiment, the first circuit 31 is specifically configured to: charge and discharge a capacitor in the capacitive coupling component 33 by controlling a transistor inside the first circuit 31, and charge the capacitor The DC power provided by the interface 10 is converted into an alternating current.

In the embodiment of the invention, the first circuit is internally provided with a transistor (such as MOS) Crystal), the transistor is prone to breakdown. When the transistor breaks down, the first circuit cannot convert the direct current into alternating current through the transistor, so that the direct current input to the charging interface is directly applied to the subsequent device or the battery of the charging circuit. However, in the embodiment of the present invention, a capacitive coupling element is disposed between the first circuit and the second circuit, and the capacitive coupling element disconnects the DC path of the charging circuit, and conducts AC and DC. That is to say, even if the transistor in the first circuit is broken down or fails, the direct current input from the charging interface cannot flow to the second circuit or the battery, thereby improving the safety of the charging circuit of the mobile terminal.

In addition, since the capacitive coupling element has good isolation performance, the on-resistance of the transistor in the first circuit can be made very low (there is no need to increase the on-resistance of the MOS transistor by increasing the on-resistance as in the prior art, thereby Increase the reliability of the circuit), which will reduce heat and loss, and improve the energy transfer efficiency of the entire charging circuit.

It should be noted that the specific form of the first circuit 31, the number of capacitors in the capacitive coupling element 33, and the connection form of the capacitances in the first circuit 31 and the capacitive coupling element 33 are not specifically limited. For example, the first circuit 31 may be a half bridge circuit or a full bridge circuit; the capacitive coupling element 33 may include one capacitor or two capacitors. In fact, as long as the specific form and connection relationship of the above circuits and components enables the first circuit 31 to transfer energy to the second circuit 32 through the capacitive coupling element. The detailed description will be made below in conjunction with specific embodiments.

Optionally, as an embodiment, the first circuit 31 may include a bridge arm circuit and a control circuit for controlling the bridge arm circuit, wherein the control circuit controls the bridge arm circuit to implement the Charge and discharge of the capacitor. For example, the first circuit 31 may include a half bridge circuit, and the capacitive coupling element 33 includes a capacitor. The first circuit 31 and the second circuit 32 are common. The first circuit 31 is connected to one end of the capacitor and the ground, and the other end of the capacitor. Grounded through the second circuit and the battery. The first circuit 31 realizes charging of the capacitor and discharging of the capacitor to the ground by controlling the half bridge circuit. Alternatively, the first circuit 31 may comprise a full bridge circuit, the capacitive coupling element 33 may comprise two capacitors, the full bridge circuit being respectively connected to the two capacitors, the first circuit 31 alternately changing the two capacitors by controlling the full bridge circuit The direction of the voltage.

It should be noted that the control circuit can be powered in various ways, for example, can be powered by a charging current or by a power source inside the mobile terminal.

Optionally, as an embodiment, the capacitor in the capacitive coupling component is one of the following capacitors: a capacitor formed by a printed circuit board (PCB), and a flexible printed circuit (FPC) board. The capacitors that make up. Alternatively, as an embodiment, the size, shape or thickness of the capacitance in the capacitive coupling element is designed based on the structure of the mobile terminal.

Specifically, the capacitance formed by the PCB board may be a capacitor specially constructed by using the PCB board and the above copper foil; the capacitor formed by the FPC board may be a capacitor specially designed by using FPC. The advantages of the capacitance of the PCB board and the capacitance of the FPC board are: it can be designed into any shape, any size, any thickness, and can be freely designed according to the structure and shape of the terminal such as a mobile phone.

Optionally, as an embodiment, the first circuit 31 may include a bridge arm circuit including a plurality of metal oxide semiconductor field effect transistors (MOSFETs).

Optionally, as an embodiment, the second circuit may include a rectifier circuit and a filter circuit.

Embodiments of the present invention are described in more detail below with reference to specific examples. It should be noted that the examples of FIG. 3 to FIG. 4 are merely intended to assist those skilled in the art to understand the embodiments of the present invention, and are not intended to limit the embodiments of the present invention to the specific numerical values or specific examples illustrated. It will be obvious to those skilled in the art that various modifications and changes can be made without departing from the scope of the embodiments of the present invention.

For example, referring to FIG. 3, the first circuit 31 can include a control circuit 311 and a half bridge circuit 312, wherein the half bridge circuit 312 can include a transistor T1 and a transistor T2. The capacitive coupling element 33 can include a capacitor C1. During the charging process, the control circuit 311 can alternately control the operation of the transistor T1 and the transistor T2 to realize charging and discharging of the capacitor C1, thereby converting the direct current into alternating current, and flowing through the capacitor C1 to the second circuit 32 and the battery 20.

Specifically, during charging, the control circuit 311 can control the electro-crystal first. The body T1 is turned on, and the transistor T2 is turned off. At this time, the direct current input from the charging interface 10 charges the capacitor C1 through the transistor T1; then, the control circuit 311 can control the transistor T1 to be turned off, and the transistor T2 is turned on, due to the first In common, circuit 31 and second circuit 32, capacitor C1 discharges to ground. The control circuit 311 repeatedly controls the operation of the half bridge circuit as described above to form an alternating current that can pass through the capacitor C1.

If the transistor in the half bridge circuit 312 is broken down, the capacitor C1 prevents the direct current output from the charging interface 10 from flowing directly to the second circuit 32 and the battery, thereby improving the reliability of the charging circuit.

For another example, see Figure 4. The first circuit 31 can include a control circuit 313 and a full bridge circuit 314, wherein the full bridge circuit 314 can include a transistor T1, a transistor T2, a transistor T3, and a transistor T4. The capacitive coupling element 33 includes a capacitor C1 and a capacitor C2. During the charging process, the control circuit 313 can first control the operation of the transistor T1 and the transistor T4, and then control the operation of the transistor T2 and the transistor T4 to alternately change the direction of the voltage in the capacitor C1 and the capacitor C2, thereby converting the direct current into The alternating current flows through the capacitor C1 and the capacitor C2 to the second circuit 32 and the battery 20.

Specifically, during the charging process, the control circuit 311 can first control the transistor T1 and the transistor T4 to be turned on, and the transistor T2 and the transistor T3 are turned off. At this time, the DC input from the charging interface 10 passes through the transistor T1. The capacitor C2, the capacitor C1, and the transistor T4 form a loop to the ground; then, the control circuit 311 can control the transistor T1 and the transistor T4 to be disconnected, and the transistor T2 and the transistor T3 are turned on. At this time, the DC input of the charging interface 10 will be The circuit is formed through the transistor T3, the capacitor C1, the capacitor C2, and the transistor T2 to the ground. The control circuit 311 repeatedly controls the operation of the full-bridge circuit as described above, and forms an alternating current that can pass through the capacitor C1 and the capacitor C2.

If the transistor in the full bridge circuit 314 is broken down, the capacitor C1 and the capacitor C2 prevent the direct current output from the charging interface 10 from flowing directly to the second circuit 32 and the battery, thereby improving the reliability of the charging circuit.

FIG. 5 is a schematic block diagram of a mobile terminal according to an embodiment of the present invention. The mobile terminal 50 includes a charging interface 51, a battery 52, and a charging circuit 53, wherein The charging circuit 53 can adopt any one of the above-described charging circuits 30.

In the embodiment of the present invention, the DC path of the charging line is separated by the capacitive coupling element, that is, there is no DC path on the charging circuit, then, when the first circuit fails, the DC output of the charging interface is not directly output. To the second circuit and the battery, the reliability of the charging circuit is improved.

Optionally, as an embodiment, the charging interface 51 is a USB interface.

Optionally, as an embodiment, the mobile terminal 50 supports a normal charging mode and a fast charging mode, wherein the charging current of the fast charging mode is greater than the charging current of the normal charging mode.

It should be understood that the phenomenon that the MOS transistor is broken down is serious in the mobile terminal supporting fast charging. Therefore, the mobile terminal using the embodiment of the present invention can well solve the line failure caused by the MOS transistor breakdown during fast charging. Reliable issues.

The embodiment of the present invention further provides a charging circuit, the charging circuit is configured to receive direct current and charge a battery, and the charging circuit includes: a first circuit connected to the input end of the direct current, and the direct current provided by the charging interface Converting to alternating current; a second circuit connected to the battery, wherein the second circuit receives the alternating current output by the first circuit, and converts the alternating current output by the first circuit into direct current to charge the battery a capacitive coupling element between the first circuit and the second circuit to open a DC path between the first circuit and the second circuit, wherein the capacitive coupling element is used in When the first circuit operates normally, the alternating current outputted by the first circuit is coupled to the second circuit, and when the first circuit is unable to generate alternating current due to a fault, the direct current output by the first circuit is blocked.

In the embodiment of the present invention, the DC path of the charging line is disconnected by the capacitive coupling element, that is, the input DC power cannot directly flow to the battery, and then, when the first circuit fails, the DC output of the charging interface is capacitively coupled. The component is blocked and will not be on the battery Cause damage.

Optionally, as an embodiment, the first circuit is specifically configured to: charge and discharge a capacitor in the capacitive coupling component by controlling a transistor inside the first circuit, and provide the charging interface DC power is converted into alternating current.

Optionally, as an embodiment, the first circuit includes a bridge arm circuit and a control circuit for controlling the bridge arm circuit, wherein the control circuit controls the bridge arm circuit to alternately implement charging of the capacitor Discharge.

Optionally, as an embodiment, the capacitor in the capacitive coupling element is one of the following capacitors: a capacitor formed by a printed circuit board (PCB), and a capacitor formed by a flexible printed circuit (FPC) board.

Optionally, as an embodiment, the first circuit comprises a bridge arm circuit, and the bridge arm circuit comprises a plurality of metal oxide semiconductor field effect transistors (MOSFETs).

Optionally, as an embodiment, the second circuit comprises a rectifier circuit and a filter circuit.

Optionally, as an embodiment, the charging circuit is used for a mobile terminal. Moreover, optionally, as an embodiment, the size, shape or thickness of the capacitance in the capacitive coupling element is designed based on the structure of the mobile terminal.

One of ordinary skill in the art will appreciate that the elements and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in the form of an electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.

It will be apparent to those skilled in the art that for the convenience and brevity of the description, the specific working processes of the systems, devices and units described above can be referred to the foregoing methods. The corresponding process in the example is not described here.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or may be Integrate into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. . Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

The functions can be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a standalone product. Based on such understanding, the technical solution of the present invention, or the part contributing to the prior art, or the part of the technical solution, may be embodied in the form of a software product stored in a storage medium, including The instructions are used to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: a portable disk, a mobile hard disk, and a read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disc, and other media that can store code.

The above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention. It should be covered by the scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the patent application.

10‧‧‧Charging interface

20‧‧‧Battery

30‧‧‧Charging circuit

31‧‧‧First circuit

32‧‧‧second circuit

33‧‧‧Capacitive coupling elements

Claims (10)

A charging circuit is disposed between the charging interface of the mobile terminal and the battery, and includes: a first circuit connected to the charging interface, wherein the first circuit receives DC power for charging through the charging interface, and The direct current provided by the charging interface is converted into alternating current; the second circuit is connected to the battery, wherein the second circuit receives the alternating current output by the first circuit, and converts the alternating current outputted by the first circuit into direct current Charging the battery; a capacitive coupling element between the first circuit and the second circuit to open a DC path between the first circuit and the second circuit, wherein The capacitive coupling element is configured to couple an alternating current outputted by the first circuit to the second circuit when the first circuit is in normal operation, and block the first circuit when the first circuit cannot generate an alternating current due to a fault The DC output of a circuit. The charging circuit of claim 1, wherein the first circuit is specifically configured to: charge and discharge a capacitor in the capacitive coupling element by controlling a transistor inside the first circuit, The direct current provided by the charging interface is converted into alternating current. The charging circuit of claim 2, wherein the first circuit comprises a bridge arm circuit and a control circuit for controlling the bridge arm circuit, wherein the control circuit controls the bridge arm circuit to alternate The charging and discharging of the capacitor is achieved. The charging circuit according to any one of claims 1-3, wherein the capacitance in the capacitive coupling element is one of the following capacitors: a capacitor formed by a printed circuit board (PCB), and a flexible printed circuit ( FPC) The capacitance of the board. The charging circuit according to any one of claims 1-3, wherein the size, shape or thickness of the capacitance in the capacitive coupling element is designed based on the structure of the charging circuit. The charging circuit of any of claims 1-3, wherein the first circuit comprises a bridge arm circuit, the bridge arm circuit comprising a plurality of metal oxide semiconductor field effect transistors (MOSFETs). The charging circuit of any one of claims 1-3, wherein the second circuit comprises a rectifier circuit and a filter circuit. A mobile terminal comprising a charging interface and a battery, wherein a charging circuit according to any one of claims 1-3 is provided between the charging interface and the battery. The mobile terminal of claim 8, wherein the charging interface is a universal serial bus USB interface. The mobile terminal of claim 8, wherein the mobile terminal supports a normal charging mode and a fast charging mode, wherein a charging current of the fast charging mode is greater than a charging current of the normal charging mode.